Fire detector



FIG. 1 is a perspective view of a fire detector, showing our new design;

FIG. 2 is a side view thereof;

FIG. 3 is a front view thereof;

FIG. 4 is side view thereof;

FIG. 5 is a rear view thereof;

FIG. 6 is a top view thereof; and,

FIG. 7 is a bottom view thereof.

The broken lines in FIG. 7 indicate unclaimed structures and form no part of the claimed design. 

The ornamental design for a fire detector, as shown and described. 